Use esbuild to minify frontend JS

This speeds up build times massively

Signed-off-by: David Mehren <git@herrmehren.de>

webpack.prod.js

@@ -1,8 +1,9 @@
 const common = require('./webpack.common.js')
 const htmlexport = require('./webpack.htmlexport')
-const { merge } = require('webpack-merge');
+const { merge } = require('webpack-merge')
 const path = require('path')
 const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin')
+const { ESBuildMinifyPlugin } = require('esbuild-loader')
 
 module.exports = [
   merge(common, {
@@ -11,6 +12,13 @@ module.exports = [
       path: path.join(__dirname, 'public/build'),
       publicPath: 'build/',
       filename: '[name].[contenthash].js'
+    },
+    optimization: {
+      minimizer: [
+        new ESBuildMinifyPlugin({
+          target: 'es2015'
+        })
+      ]
     }
   }),
   merge(htmlexport, {